This invention relates to an apparatus for chopping and discharging straw from a combine harvester which includes a plurality of blade members mounted on a hub for rotation about an axis of the hub with the blade members being arranged at spaced positions along the length of the hub substantially in radial planes of the hub so as to pass between a plurality of axially spaced stationary blades again arranged in radial planes of the hub. The straw and other material discharged from the combine is fed into one side of the housing of the apparatus onto the hub and the material is carried around by the hub past the stationary blades in a chopping action. The material is then discharged from a discharge opening in the housing for collection or spreading across the field.
The present invention is particularly an improvement over the arrangement disclosed in U.S. Pat. No. 5,232,405 of the present inventors issued Aug. 3, 1993 based on an application filed Jan. 7, 1992. This arrangement shows a support plate lying in a radial plane and an additional plate or flap at right angles to the support plate to so that the additional plate lies longitudinally of the hub. The additional plate is inclined so that a radially outer edge of the additional plate lies angularly forwardly of a radially inner edge of the plate. The additional plate is welded across a trailing edge of the support plate and extends out to both sides of the support plate.
This arrangement has achieved some commercial and technical success and the present invention is directed to a yet further improvement which builds upon the improvement of the previous patent.
A further arrangement relevant to the present invention is that shown in U.S. Pat. No. 5,042,973 of Hammarstrand which discloses a similar chopping and discharge apparatus having rotating blade members carried on a hub and stationary blades fixed to the housing. The blade members are mounted in pairs so that a single lug carried on the hub supports a transverse pin parallel to the axis of the hub with the blade members mounted on respective sides of the lug and carried on bushings mounted on the pin. The blade members are spaced so that each blade member passes between two of the stationary blades in a cutting action. The blade members are shaped so as to be arch shaped in each cross section transverse to the length of the blade member thus defining a sharpened cutting edge at the leading edge and a sharpened cutting edge at the trailing edge with a center section of the blade bowed outwardly of a plane containing the leading and trailing edges. The blades are shown in face to face or back to back arrangements of the pairs.
A yet further arrangement is shown in U.S. Pat. No. 3,693,335 (Mathews) which shows blades which are inclined from the normal radial plane so as to extend outwardly from the hub in a direction which is inclined to the radial and axial directions.